original research evaluation of the upper airway ...nasopharyngeal airway (na) in adults with a...

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International Dental Journal of Student’s Research, December 2015;3(4):174-183

ORIGINAL RESEARCH

Evaluation of the Upper Airway Morphology in Patients with Class II Malocclusion Using 3-Dimentional Computed Tomography Ali Alkhayer1 Fadi Khalil2 Hazem Hasan3 1MSc Student, Department of Orthodontics, Faculty of

Dentistry, Tishreen University, Lattakia, Syria 2Ass. Professor at Orthodontics and Dentofacial Orthopedic

Department, Dental School, Tishreen University, Lattakia,

Syria 3Professor at Orthodontics and Dentofacial Orthopedic

Department, Dean of the Faculty of Dentistry, Tishreen

University.

Corresponding Author:

E-mail: [email protected].

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Abstract Introduction: It is common nowadays that respiratory

functions are highly relevant to the orthodontic diagnosis

and the treatment plan, besides their effects on the

stability of the treatment results. So it is important to

have a better and more deeply analysis of the upper

airway morphology in our patients, especially, in class II

patients where the upper airway could be affected by the

pressures against the dentition, dental arch form, and the

possibly direction of mandibular and maxillary growth.

Objective: The aim of this study was to evaluate the size

and areas of the upper airways in adults with skeletal

Class II malocclusion, using three dimensional

computed tomography (3DCT) and to compare the

cross-sectional measurements and cephalometric

variables with skeletal class I group, to investigate

possible relationships between the upper airway and

anteroposterior growth type.

Materials and methods: Our Sample's consisted of 36

adults (15males, 21 females) who were selected from

patients who were ordinary undergoing 3DCT for non-

orthodontic nor otolaryngology purpose and didn’t have

orthodontic treatment. The anteroposterior positions of

both the maxilla and the mandible were evaluated with

the ANB angle, AF-BF distance, Wits appraisal to divide

our subjects into 2 groups: (1) skeletal Class I patient’s

with2 >ANB<5, and (2) skeletal Class II patients with

ANB >5. Then we calculated Pearson's Correlation to

investigate the possible relationship between the upper

airway measurements and the Cephalometric measure-

ments determining anteroposterior growth patterns.

Results: we found statistically significant correlation

between nasopharyngeal airway measurements and the

cephalometric measurements determining anteropos-

terior growth patterns. The depth and area of NA showed

negative correlation with ANB, WITS, AF-BF (p＜

0.05). We also found that this depth and area were

smaller in class II. We didn’t see significant differences

between males and females in airway measurements.

Conclusions: The skeletal Class II malocclusion had a

narrower nasopharyngeal airway than the Class I group,

there is a statistically significant correlation between

nasopharyngeal airway measurements and the


terior growth patterns.

Key words: Upper airway Morphology, 3DCT, Class II

malocclusion, Anteroposterior growth type.

Introduction Several lines of evidence from cephalometric studies

support a link between presumed respiratory mode and

facial morphology[1]. For that, the effects of respiratory

function on craniofacial growth have been studied for

decades, and most clinicians now understand that

respiratory functions is highly relevant to the orthodontic

diagnosis and to the treatment plan. Accordingly, much

attention has been paid to the relationship between

respiratory function and facial morphology in

orthodontics[2]. In 1907, Angle [3] showed that his Class

II Division 1 malocclusion is associated with obstruction

of the upper pharyngeal airway and mouth breathing.

A common cause of mouth breathing arises from the

adenoids, which are a conglomerate of lymphatic tissues

located in the posterior pharyngeal airway. Infection and

mailto:[email protected]

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inflammation of the adenoids leads to upper airway

obstruction, and the term ‘‘adenoid facies’’ is often used

to describe a possible aberrant craniofacial growth

pattern, which is related to mouth breathing and

characterized by lip incompetency, underdeveloped

nose, increased anterior facial height, constricted dental

arches, and proclined maxillary incisors with a Class II

occlusal relationship [4-6]. This reasonable link between

respiratory mode and the development of malocclusion

could be soft-tissue pressures against the dentition that

might affect tooth eruption, dental arch form, and

possibly the direction of mandibular and maxillary

growth [1]. Rosen CL (2004) found that Class II patients

have a narrower anteroposterior pharyngeal dimension,

and this narrowing is specifically noted in the

nasopharynx at the level of the hard palate and in the

oropharynx at the level of the tip of the soft palate and

the mandible [7]. Class II Division 1 malocclusion is

associated with a narrower upper airway even without

retrognathia [8].

Park et al noticed that the Inclination of the

oropharyngeal airway might be a key factor in

determining the form of the entire pharyngeal airway,

and found that Children with Class II malocclusion have

more backward orientation and smaller volume of the

pharyngeal airway than do children with Class I and III

malocclusion [9]. Hwang et al reported that a constricted

nasopharyngeal airway is associated with detruded

mandible and maxilla [10]. Grauer et al found in their

recent CBCT study a potential influences of the

anteroposterior growth type on the airway dimensions

and shape, and they noticed that the inferior

compartment airway volume was smaller in skeletal

Class II than in Class I and Class III patients. They also

found that Subjects with Class II skeletal pattern was

associated with a more forward orientation of the airway

compared with the other groups [1].

In addition to studies that affirm nasal obstruction as the

major factor responsible for dentofacial anomalies, other

studies refute a significant relationship between airway

obstruction and the frequency of malocclusion. In a

study of 500 patients with upper airway problems, Leech

[11] discovered that 60% of the mouth-breathing patients

were Class I and concluded that mouth breathing has no

influence on craniofacial growth. Similarly, Gwynne-

Evans [12] determined that facial growth is constant

regardless of the mode of breathing.

Morphometric evaluation of the pharyngeal airway has

been mostly performed on lateral cephalometric head

films, by identifying specific landmarks and measuring

various lengths and areas in the pharyngeal region [3-

5,11,12]. Despite the vast amount of researches

concerning airway anatomy and its influence on

craniofacial growth and development, this technique has

been concerned limited, because it provides 2-

dimensional (2D) images of complex 3-dimensional

(3D) anatomic structures[13]. New 3-dimensional (3D)

technology of computed tomography (CT) has expanded

diagnostic capacities, making volumetric analysis and

accurate visualization of the airway possible, and has the

advantage of high-quality images to discern hard- and

soft-tissue anatomies. Cross-sectional and volumetric

investigations of the pharyngeal airway have been

possible by using 3DCT scans to analyze the complex

airway anatomy, and previous studies have confirmed

that volumetric measurements of airways with 3DCT are

accurate with minimal error [14].

Accordingly, the purpose of this study was to carry out

an evaluation of the oropharyngeal airway (OA) and

nasopharyngeal airway (NA) in Adults with a skeletal

Class II malocclusion by using 3-Dimentional computed

tomography (3DCT) and 3-dimensional (3D) image

reconstruction software, (ie, cross-sectional area [CSA]),

depth, and width in the horizontal plane of adults with

class II malocclusion were measured and compared with

adults with Class I. The null hypothesis was that Class II

and Class I patients do not differ in airway dimensions.

Material and Methods -subjects

Sample's subjects were selected from patients who were

ordinary undergoing 3DCT scan neither for orthodontic

nor for otolaryngology purpose and they didn’t get an

orthodontic treatment. The criteria for selecting the

subjects were taken as follows:

1. No visual, hearing, or swallowing disorders and no

history of speech-language pathology

2. No history of hyperplasia of tonsils and adenoids,

tonsillectomy or adenoidectomy and those with

OSA, nasal respiratory complex surgery for the

control group.

3. No history of trauma to the dento-facial structures.

4. Each subject must have fully erupted permanent

dentition up to second molar.

Exclusion criteria were subjects with congenital

anomalies/ evident signs of neurological impairment

and/or syndromes or dentoskeletal asymmetries and

craniofacial malformation.

Sample estimation

To determine the minimum sample size to be statistically

significant, a similar previous study was realized on 45

subject (who were selected according to the criteria of

selecting this study`s sample). It has been found that

descriptive statistics results follow the normal

distribution; therefore, determining the minimum sample

size to be statistically significant was according to the

following formula:

(N): is the sample size; (z): is the value corresponding to

a confidence level, estimated at 99% (Z = 2.58) (i.e.

significance level is 0.019), (σ): highest Standard

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Deviation value within the all linear and angular

variables at the pilot study (σ = 7.92)

(e): Margin of error (maximum acceptable error in mean

estimate) (e=5). Thus:

According to that previous study, the sample size (n)

must be as minimum of 16.7 patients, whereas sample

size of this study was n=36.

A total of 36 patients (15 males, 21 females, mean age

31 years), who came for non-orthodontic nor

otolaryngology purpose were participated in this study.

- 3DCT – Study

The CT images were made with a multislice CT at Al-

Assad University Hospital (Toshiba, Aquilion 64 slices,

2008) with a high-resolution bone algorithm, 512 _ 512

matrix, 120 KV, and 300 mA. The thickness of the axial

images 0.5 mm and exposure time of 9.6 seconds.

The subjects were positioned with the Frankfort

horizontal (FH) line perpendicular to the floor and the

facial midline coinciding with the long axis of the CT

machine. The image covered the area from the vertex to

the inferior border of the mandibular body.

The patients were instructed not to breathe deeply, not to

swallow, to maintain the teeth in maximum

intercuspation, and not to move the head and tongue

during scanning. The axial images were transformed to

the DICOM (Digital Imaging and Communications in

Medicine) format and reconstructed into a 3D model by

using Ondemand 3d app version 1.0 (CyberMed).

Fig. 1: program was used to measure the 3D models

Then, on multiple planar reconstruction (MPR) images, The head 3D reconstructions of each patient were re-oriented

using the Frankfurt (FH) plane as the horizontal reference plane [15,16]

The origin of the 3D coordinate system was the midpoint between the left and right porions. This origin and left and

right orbitale defined the standard horizontal plane. A frontal plane was constructed through both orbitale points and

perpendicular to the horizontal plane. The sagittal plane was constructed through both orbitale midpoints and

perpendicular to the horizontal and frontal planes [17].

n =

5²

≈ 16.7 (2.58)²(7.92)²

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3DCT measurements

Airway cross-sectional measurements included CSA, depth (anteroposterior direction), and width (left-right

direction). The CSAs of the nasopharyngeal and oropharyngeal airways were defined as shown in Figure 2. Three

parameters for the size of the nasopharyngeal and oropharyngeal airways were determined based on previous reports

[18,19]. The nasopharyngeal airway cross-section was measured along a horizontal plane at the airway’s narrowest

part on the cephalometric image. The OA cross-section was measured along a horizontal plane passing through the

midpoint of bilateral gonion. A Hounsfield unit range of 300 to 1024– was interpreted to be air [17].

Fig. 2: Measurements of the nasopharyngeal airway (NA) and the oropharyngeal (OA

-lateral cephalometric analysis:

Since 2-dimensional (2D) images produced from three dimensional computed tomography (3DCT) images could

substitute for traditional cephalograms [17], in this study, lateral cephalometric analysis was obtained by Kumar

method (2008) using 2-dimensional images produced from 3-dimentional computed tomography, which were

achieved in centric occlusion [20].

From this cephalometric image, the anteroposterior positions of both the maxilla and the mandible were evaluated

with the ANB angle [21], AF-BF (the distance between perpendiculars drawn from A-point and B-point onto the

Frankfort horizontal plane) [22], Wits appraisal [23].

We divided our subjects into 2 groups according to the occlusion: (1) skeletal Class I patients(12 female and 7

male)with2 >ANB<5,and (2) skeletal Class II patients(9 female and 8 male)with ANB >5.

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Statistical analysis T tests were used to compare (1) the anteroposterior position of the maxilla and the mandible; (2) the size of the upper

airway (CSA, width, depth). The Pearson product-moment correlation coefficients were calculated to evaluate the

relationships among CSA, depth, and width of the OA and the NA, and correlations between the measurements of the

OA, NA and the anteroposterior position of the maxilla and the mandible in the Class II group. Then Mann-Whitney

analysis for small samples was used to evaluate the correlation between the upper airway measurements and gender

in class I and class II groups, and to investigate the differences between males and females in these measurements.

- Error of method:

All cephalometric and 3DCT measurements were repeated twice with a month interval, by the same calibrated

investigator using the same workstation, the initial measurements and the repeated measurements were compared by

using a paired t-test at α= 0.05 to check any systematic error. The t-test did not show any statistical significance.

Results Descriptive statistics for anteroposterior measurements of the maxilla and the mandible are presented in table 1.

Table 1: Cephalometric measurements of the anteroposterior position of the maxilla and the mandible

CLASS II CLASS I

Sig t Mean SD Mean SD

.110 1.639 80.4353 3.59582 82.3579 3.43904 SNA(º)

**.000 1.635 74.3118 3.47543 79.1421 3.04363 SNB(º)

**.000 4.446 6.6235 1.49228 3.2158 1.03562 ANB(º)

**.000 -7.367- 5.5029 1.77653 .5837 2.17993 Wits(mm)

**.000 -8.036- 8.6806 1.83882 4.0663 1.60684 AF-BF(mm)

** Statistically significant at P< 0.01.

Descriptive statistics for OA and NA measurements in class I and class II are presented in table 2.

Table 2: Mean measurements of OA and NA measurements in class I and class II

CLASS II CLASS I

t Sig Mean SD Mean SD

1.311 .199 11.4347 2.60916 13.1321 4.72964 Depth(mm)

Oropharyngeal

Airway .250 .804 22.2282 4.80545 22.6637 5.54768 Width(mm)

1.103 .278 209.4547 85.76856 250.4763 130.06426 Area(mm²)

6.511 .000** 12.6959 2.09679 18.2437 2.89749 Depth(mm)

Nasopharyngeal

Airway .789- .436 27.1806 3.94701 26.1884 3.59775 Width(mm)

3.571 .001** 267.8994 69.87441 348.9889 66.32639 Area(mm²)

**.Statistically significant at P< 0.01.

Graphical diagrammatic for OA and NA measurements and areas in class I and class II subjects are presented in graph

1.

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Graph 1: Graphical diagrammatic for OA and NA measurements in class I and class II.

Results of Pearson's Correlation test between the measurements of OA and NA of the Class I and Class II groups are

presented in table 3.

Table 3: Correlations among the OA and NA measurements of the Class I and Class II groups

Depth Width

Class I

group

Oropharyngeal airway CSA (.000)**.889 (.002)**.671

Depth - .380 (.109)

nasopharyngeal airway CSA .401(.088) (.001)**.691

Depth - -.153-(.531)

Class II

group

Oropharyngeal airway CSA (.000)**.883 (.000)**.787

Depth - (.027)*.536

nasopharyngeal airway CSA (.001)**.736 (0.05)**.653

Depth - .237 (.360)

*Statistically significant at P <0.05; **Statistically significant at P<0.01.

0

2

4

6

8

10

12

14

16

18

20

Oropharyngeal airwayDepth

Nasopharyngeal airwayDepth

class I class II

0

5

10

15

20

25

30

Oropharyngeal airwayWidth

Nasopharyngeal airwayWidth

class I class II

0

50

100

150

200

250

300

350

400

Oropharyngeal airway Area Nasopharyngeal airway Area

class I class II

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Results of Pearson's Correlation test between OA and NA measurements and all cephalometric measurements

determining anteroposterior growth patterns within all subjects of the sample (regardless of gender) are presented in

table 4.

Table 4: Correlations between the anteroposterior position of the maxilla and the mandible and the OA, NA

measurements

Oropharyngeal airway nasopharyngeal airway

Depth Width CSA Depth Width CSA

SNA (P)

-.004- .021 .009 .159 .053 .266

.982 .901 .956 .353 .761 .117

SNB (P)

.086 .063 .125 .346* -.114- .320

.619 .716 .468 .039 .507 .057

ANB (P)

-.130- -.065- -.139- -.551-** .118 -.313-*

.451 .705 .420 .000 .492 .050

Wits(p)

-.193- -.178- -.193- -.541-** .260 -.233-

.260 .300 .258 .001 .125 .172

AF-BF(p) -.004- -.097- -.045- -.467-** .006 -.356-*

.982 .575 .795 .004 .971 .048


Table 5: Correlations between the anteroposterior position of the maxilla and the mandible and the OA, NA

measurements of the Class II group

Class II nasopharyngeal airway Oropharyngeal airway

Depth Width CSA Depth Width CSA

ANB (P) .259 .082 .218 .024 .148 -.054-

.315 .756 .400 .927 .570 .836

Witz(p) .479 .362 .278 -.453- -.389- *-.534-

.052 .012 .021 .068 .123 .027

AF-BF(p) .245 -.150- .212 -.019- -.216- -.126-

.343 .566 .414 .942 .405 .630


Descriptive statistics for OA and NA measurements in class I and class II (both genders, male, female) are presented

in table 6.

Table 6: Mean measurements of the upper airway in males and females in each group.

Class Gender Oropharyngeal airway nasopharyngeal airway

Depth

(mm)

Width

(mm)

Area

(mm²)

Depth

(mm)

Width

(mm)

Area

(mm²)

Class I Male Mean 17.02 23.23 339.44 17.31 26.60 362.58

Std. D 4.41 6.17 160.50 2.85 3.62 69.69

Female Mean 10.86 22.32 198.58 18.78 25.94 341.06

Std. D 3.27 5.40 75.20 2.90 3.72 66.05

Class II Male Mean 11.97 21.86 206.63 12.51 26.57 254.19

Std. D 3.15 5.77 96.06 2.18 3.68 56.92

Female Mean 10.95 22.55 211.96 12.85 27.71 280.08

Std. D 2.08 4.09 81.37 2.13 4.31 81.08

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Table 7: Mann-Whitney analysis of the measurements of the upper airway in class I

Class I Oropharyngeal airway nasopharyngeal airway

Depth Width area Width Depth area

Mann-Whitney U 8.000 41.000 20.000 32.000 37.000 33.000

Wilcoxon W 86.000 119.00 98.000 60.000 115.00 111.00

Z -2.876- -.085- -1.859- -.845- -.423- -.761-

Asymp. Sig. (2-tailed) .004 .933 .063 .398 .673 .447

Exact Sig. [2*(1-tailed Sig.)] .003 .967 .068 .432 .711 .482

Table 8: Mann-Whitney analysis of the measurements of the upper airway in class II

CLASS II Oropharyngeal airway nasopharyngeal airway

Depth Width area Width Depth area

Mann-Whitney U 32.000 34.500 35.000 31.000 32.000 31.000

Wilcoxon W 77.000 79.500 80.000 67.000 68.000 67.000

Z -.385- -.144- -.096- -.481- -.385- -.481-

Asymp. Sig. (2-tailed) .700 .885 .923 .630 .700 .630

Exact Sig. [2*(1-tailed Sig.)] .743 .888 .963 .673 .743 .673

Discussions The main aim of this study was to establish the

characteristics of the OA and NA in adults with skeletal

Class II malocclusion Using 3DCT, and to investigate

possible relationships between the upper airway and

anteroposterior growth type. Skeletal patterns according

to the ANB angle were chosen, because this is one of the

most used criteria in the determination of the

anteroposterior relationship between the maxilla and the

mandible [24-28]. Nevertheless, this angle might be

influenced by the anteroposterior position of nasion

relative to Points A and B, among other factors, and

some authors have suggested that the diagnosis of such

discrepancies must be based on more than 1

anteroposterior appraisal [26,29-30], so we included wits

value, AF-BF distance to support our results.

The subjects ranged from 17 to 42 years of age (average,

31 years), so they had already undergone their adolescent

growth spurt; thus, we did not evaluate the correlation

between airway measurements and age. In the progress

of sampling, we found statistically significant correlation

between nasopharyngeal airway measurements and the


terior growth patterns (table 4), and this was in

agreement with Grauer et al 2009 [1], who found

statistically significant relationship between the volume

of the inferior component of the airway and the

anteroposterior jaw relationship.

We found that class II subjects have smaller depth and

area of nasopharyngeal airway than class I (table2), Park

et al ,2011[9] found in their subjects that Children with

Class II malocclusion have smaller volume of the

pharyngeal airway than do children with Class I and III

malocclusion. Claudino et al, 2013 also found The Class

II subjects had smaller minimum and mean areas (lower

pharyngeal portion, velopharynx, and oropharynx) than

did the Class I, III groups. [31] Alves et al [32] compared

3D airways of adult skeletal Class II and Class III

patients, and concluded that pharyngeal airway width

had statistical significance differences between the 2

groups, whereas we didn’t see any significant differences

in airway width in our subjects. These differences could

be related to the use of different subjects, different

positions and projected planes. The OA measurements in

class II group were also smaller than class I, but not

significant.

Within our subjects regardless the anteroposterior

position, Pearsonˈs correlation test showed:

strong negative correlation between each of ANB

angle, wits value and the Depth of NA, and

moderate negative one between ANB angle and

nasopharyngeal airway CSA, and that means: the

greater the ANB angle, the smaller the NA depth

and area.

Moderate negative correlation between AF-BF and

between the Depth and CSA of NA.

Moderate positive correlation between SNB angle

and the Depth of NA, and that means that in angel

class II, the less anteroposterior growth or position

of the mandible, the less depth of nasopharyngeal

airway, (table 4)

Claudino et al, 2013 found a negative correlation

between the ANB value and airway volume in the lower

pharyngeal portion and the velopharynx (both sexes) and

in the oropharynx (just in male subjects) [31]. Within our

class II subject regardless gender, Pearsonˈs correlation

test showed strong negative correlation between wits

value and the CSA of the Oropharyngeal airway. We also

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found very strong positive correlation between the CSA

of both of OA and NA with their depth and width, and a

moderate positive correlation between the depth and

width of the OA in class II subject (table 3). Regarded to

gender, we didn’t see any significant differences

between males and females in airway measurements

except in Oropharyngeal depth of class I subjects,

females have narrower OA depth than males. Grauer et

al 2009 [1] also didn’t find statistically significant

relationship between volume of the airway and sex.

Whereas Shigeta et al [33] found larger airway volumes

in men than in women.

Maybe the small sample size in our study did not allow

an adequate statistical appreciation of the differences

between the sexes. With larger numbers in each group,

other differences would have been statistically

significant. So further studies with larger groups are

recommended.

Conclusions 1. The Class II malocclusion had a narrower

nasopharyngeal airway than the Class I group.

2. There is a strong correlation between the depth and

area of NA and each of ANB, WITS, AF-BF.

3. No differences in airway measurements between

males and females except in Oropharyngeal depth of

class I subject, but we still need further studies with

larger samples to have more accurate results.

References: 1. Grauer et al. Pharyngeal airway volume and shape from

cone-beam computed tomography: Relationship to facial

morphology. Am J OrthodDentofacialOrthop. 2009

December;136(6):805–814. doi: 10.1016/j.ajodo.2008.01.

020

2. Melsen B. Current controversies in orthodontics. Chicago:

Quintessence;1991.

3. Angle E. Treatment of malocclusion of the teeth.

Philadelphia: SSWhite Manufacturing Company; 1907.

4. Ricketts RM. Respiratory obstruction syndrome. Am J

Orthod1968;54:495-507.

5. Linder-Aronson. Adenoids and their effect on mode of

breathing and nasal airflow and their relationship to

characteristics of the facial skeleton and the dentition. A

biometric, rhino-manometric and cephalometro-

radiographic study on children with and without adenoids.

Acta Otolaryngol Suppl 1970;265:1-132.

6. Moore A. Observations on mouth breathing. Bull N Z

SocPeriodontol1972;9-11.

7. Rosen CL. Obstructive sleep apnea syndrome in children:

controversiesin diagnosis and treatment. PediatrClin North

Am 2004;51:153-67.

8. Kirjavainen M, Kirjavainen T. Upper airway dimensions

in ClassII malocclusion. Effects of headgear treatment.

Angle Orthod2007;77:1046-53.

9. Park et al :2011 .Three-dimensional analysis of pharyngeal

airway form in children with anteroposterior facial

patterns. Angle Orthod. 2011;81:1075–1082.

10. Hwang YI, Lee KH, Lee KJ, Kim SC, Cho HJ, Cheon SH,

et al. Effect of airway and tongue in facial morphology of

prepubertal Class I, II children. Korean J Orthod

2008;38:74–82.

11. Leech H. A clinical analysis of orofacial morphology and

behaviorof 500 patients attending an upper respiratory

research clinic.Dent Pract 1958;9:57-68.

12. Gwynne-Evans E. Discussion on the mouth-breather. Proc

R SocMed 1958;51:279-82.

13. Preston, CB. The upper airway and cranial morphology.

In: Graber, TM.; Vanarsdall, R.; Vig, KWL.,editors.

Orthodontics: principles and techniques. 4th ed.. St Louis:

C.V. Mosby; 2005. p. 117-143.

14. Aboudara C, Nielsen I, Huang JC, Maki K, Miller AJ,

Hatcher D.Comparison of airway space with conventional

lateral headfilms and 3-dimensional reconstruction from

cone-beam computed tomography. Am J Orthod

Dentofacial Orthop 2009;135:468-79.

15. ALVESJR M, BARATIERI C, NOJIMA LI. Assessment

of mini-implant displacement using cone beam computed

tomography. Clin Oral Implants Res 2011, 10.1111/j;

1600- 0501.2010.02092.x.

16. BARATIERI C, NOJIMA LI, ALVESJR M, Souza MMG,

Nojima MG. Transverse effects of rapid maxillary

expansion in Class II malocclusion patients: a cone-beam

computed tomography study. Dental Press J

Orthod2010;15:89–97.

17. Iwasaki et al .Oropharyngeal airway in children with Class

III malocclusion evaluated by cone-beam computed

tomography. Am J Orthod Dentofacial Orthop

2009;136:318.e1-318.e9

18. KYUNG SH, PARK YC, PAE EK. Obstructive sleep

apnea patients with the oral appliance experience

pharyngeal size and shape changes in three dimensions.

Angle Orthod 2005;75:15-22

19. LAMICHANE M, ANDERSON NK, RIGALI PH,

SELDIN EB, WILL LA. Accuracy of reconstructed

images from cone-beam computed tomography scans. Am

J Orthod Dentofacial Orthop. 2009 Aug;136(2).

20. KUMAR V., LUDLOW J, SOARES CEVIDANES LH,

MOL A. In vivo comparison of conventional and cone

beam CT synthesized cephalograms. Angle Orthod. 2008

Sep;78(5):873-9

21. Riedel RA. The relation of maxillary structures to cranium

in malocclusion and in normal occlusion. Angle Orthod

1952;22:140-5.

22. Chang HP. Assessment of anteroposterior jaw relationship.

Am J Orthod Dentofacial Orthop 1987;92:117-22.

23. Jacobson A. The ‘‘Wits’’ appraisal of jaw disharmony. Am

J Orthod 1975;67:125-38.

24. Oz U, Orhan K, Rubenduz M. Two-dimensional lateral

cephalometric evaluation of varying types of Class II

subgroups on posterior airway space in postadolescent

girls: a pilot study. J Orofac Orthop. 2013;74:18–27.

25. Ucar FI, Uysal T. Orofacial airway dimensions in subjects

with Class I malocclusion and different growth patterns.

Angle Orthod 2011; 81:460-8.

26. Kim YJ, Hong JS, Hwang YI, Park YH. Three-

dimensional analysis of pharyngeal airway in

preadolescent children with different anteroposterior

skeletal patterns. Am J Orthod Dentofacial Orthop

2010;137:306.e1-11; discussion 306-7.

27. El H, Palomo JM. Airway volume for different dentofacial

skeletal patterns. Am J Orthod Dentofacial Orthop

2011;139:511-21.

28. Alves M Jr, Franzotti ES, Baratieri C, Nunes LK, Nojima

LI, Ruellas AC. Evaluation of pharyngeal airway space

amongst different skeletal patterns. Int J Oral Maxillofac

Surg 2012;23:1-6.

29. Hussels W, Nanda RS. Analysis of factors affecting angle

ANB. Am J Orthod 1984;85:411-23.

{183}


30. Ferrario VF, Sforza C, Miani A Jr, Tartaglia GM. The use

of linear and angular measurements of maxillo-mandibular

anteroposterior discrepancies. Clin Orthod Res 1999;2:34-

41.

31. Claudino et al, Pharyngeal airway characterization in

adolescents related to facial skeletal pattern: A preliminary

study. Am J Orthod Dentofacial Orthop 2013;143:799-

809)

32. Alves PV, Zhao L, O’Gara M, Patel PK, Bolognese AM.

Three-dimensional cephalometric study of upper airway

space in skeletal Class II and III healthy patients. J

Craniofac Surg 2008;19: 1497-507.

33. Shigeta Y, Ogawa T, Venturin J, Nguyen M, Clark GT,

Enciso R. Gender- and age-based differences in

computerized tomographic measurements of the

orophaynx. Oral Surg Oral Med Oral Pathol Oral Radiol

Endod 2008;106:563-70.

original research evaluation of the upper airway ...nasopharyngeal airway (na) in adults with a...

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